摘要
综合利用超压测井响应特征、盆地数值模拟、流体包裹体分析、已钻井岩心观察、薄片鉴定等研究手段,结合天然气成藏地质条件剖析,对琼东南盆地深水区乐东—陵水凹陷中新统梅山组气藏超压特征、成因机制进行了分析,并探讨了储层强超压的形成与天然气成藏过程的耦合关系,明确了其成藏模式。研究结果表明:①乐东—陵水凹陷梅山组压力为49.74~95.76 MPa,压力系数为1.37~2.09,为超压—强超压,单井压力结构表现为典型的双层超压结构;超压成因早期主要受欠压实作用控制,晚期则受烃类流体增压传导与欠压实作用共同控制。②研究区天然气由渐新统与中新统烃源岩混合供烃,存在3期油气充注,第1期(6.0 Ma)为液态烃充注,第2期(2.7 Ma)开始烃类气充注,成藏高峰期为1.9~1.0 Ma,第3期(1.8~1.2 Ma)为CO_(2)充注。③研究区梅山组储层强超压的形成与天然气运移成藏过程密切相关,超压为油气运移提供了关键驱动力,有利于形成断裂和微裂隙等泄压通道;多期含烃类酸性流体的充注导致了有机酸的溶蚀改造,有效促进了次生溶孔的发育;晚期超压对储层孔隙的保存具有积极意义。梅山组天然气成藏具有“多源供烃—超压驱动—垂向裂隙输导—多期充注—大型砂体汇聚—近源超压溶蚀型储层优先富集”的特征。
Comprehensively utilizing overpressure logging response characteristics,basin numerical simulation,fluid inclusion analysis,drilled core observation,and thin section identification,combined with the analysis of geological conditions for natural gas accumulation,the overpressure characteristics and genesis mechanism of Miocene Meishan Formation gas reservoir in Ledong-Lingshui Sag of the deep water area in Qiongdongnan Basin were analyzed.The coupling relationship between reservoir strong overpressure formation and natural gas accumulation process was explored,and the reservoir formation mode was clarified.The results show that:(1)The pressure of Meishan Formation in Ledong-Lingshui Sag ranges from 49.74 to 95.76 MPa,with a pressure coefficient of 1.37-2.09,which is overpressure-strong overpressure.The pressure structure of a single well shows a typical double-layer overpressure structure.In the early stage,overpressure was mainly controlled by un dercompaction,while in the late stage,it was jointly controlled by hydrocarbon fluid pressurization and undercompaction.(2)Natural gas in the study area is jointly sourced by Oligocene and Miocene source rocks,with three stages of oil and gas charging.The first stage(6.0 Ma)was liquid hydrocarbon charging,the second stage(2.7 Ma)was hydrocarbon gas charging,and the peak period of reservoir formation was 1.9-1.0 Ma.The third stage(1.8-1.2 Ma)was CO_(2) charging.(3)The strong overpressure in Meishan Formation reservoir in the study area is closely related to the process of natural gas migration and accumulation.Overpressure provides a key driving force for oil and gas migration,which is conducive to the formation of pressure relief channels,such as fractures and microcracks.The multi-stage injection of hydrocarbon containing acidic fluids leads to organic acid dissolution and transformation,effectively promoting the development of secondary dissolution pores.Late overpressure has a positive impact on the preservation of reservoir pores.Meishan Formation natural gas reservoir has the characteristics of“multi-source hydrocarbon supply-overpressure drive-vertical fracture transport-multistage filling-large sand body aggregation-preferential enrichment of near source overpressure dissolution type reservoirs”.
作者
刘海钰
胡林
刘兵
庹雷
李虎
江汝锋
吴仕玖
LIU Haiyu;HU Lin;LIU Bing;TUO Lei;LI Hu;JIANG Rufeng;WU Shijiu(Hainan Branch of CNOOC Ltd.,Haikou 570100,China)
出处
《岩性油气藏》
北大核心
2025年第5期70-82,共13页
Lithologic Reservoirs
基金
中国海洋石油有限公司综合科研项目“琼东南盆地他源超压模拟及预测方法研究”(编号:KJZH-2025-2101)资助。
关键词
古压力演化
异常高压
欠压实超压
油气充注超压
多源供烃
梅山组
中新统
乐东—陵水凹陷
琼东南盆地
paleo-pressure evolution
abnormal high pressure
undercompaction overpressure
overpressure during oil and gas filling
multi-source hydrocarbon supply
Meishan Formation
Miocene
Ledong-Lingshui Sag
Qiongdongnan Basin
